Blends of styrene/acrylonitrile copolymers with block copolymers containing lactones

ABSTRACT

THE IMPACT STRENGTH OF STYRENE/ACRYLONITRILE COPOLYMERS IS GREATLY IMPROVED BY BLENDING THERWITH A CONJUGATED DIENE BLOCK COPOLYMER CONTAINING A LACTONE.

United States Patent Oifice 3,649,716 BLENDS F STYRENE/ACRYLONITRILE C0-POLYMERS WITH BLOCK COPOLYMERS CONTAINING LACTONES Clifford W. Childersand Earl Clark, Bartlesville, 0kla., assignors to Phillips PetroleumCompany No Drawing. Filed Apr. 17, 1970, Ser. No. 29,687 Int. Cl. C08f41/12 US. Cl. 260-893 7 Claims ABSTRACT OF THE DISCLOSURE The impactstrength of styrene/acrylonitrile copolymers is greatly improved byblending therewith a conjugated diene block copolymer containing alactone.

This invention relates to a method for improving the impact strength ofstyrene/acrylonitrile copolymers. This invention further relates to anovel composition comprising a blend of styrene/acrylonitrile copolymersand a conjugated diene block copolymer containing a lactone wherein saidlactone block forms a solid solution with said styrene/acrylonitrilecopolymer.

A method has now been discovered for greatly improving the impactstrength of resinous styrene/acrylonitrile copolymers while essentiallymaintaining or improving other important properties of the copolymersuch as fluxural modulus, tensile, and elongation. It has thus beensurprisingly discovered that the impact strength of styrene/acrylonitrile copolymers is greatly improved by blending therewith aconjugated diene block copolymer containing a lactone.

A novel homogeneous polymer mixture has also been discovered in that ithas been found that there is a true solubilit betweenstyrene/acrylonitrile copolymers and the lactone segment of said blockcopolymers.

Our invention is particularly surprising in view of the fact that theimpact strength of styrene/acrylonitrile copolymers is greatly improvedonly when the lactone polymer that is blended therewith is in the formof a block polymer containing said lactone in contrast to a polylactonesuch as a lactone homopoly-mer. Said lactone homopolymers, even at highconcentrations and in spite of appearing to be completely compatibletherewith, were comparatively ineffective for improving the impactstrength of the styrene/acrylonitrile copolymers. Our invention iscompletely unexpected in that blends of styrene/acrylonitrile copolymerswith other polymers such as polybutadiene and rubbery butadiene/styrenecopolymers were also comparatively ineffectual for improving the impactstrength of styrene/acrylonitrile copolymers. Another startling fact isthat when said lactone block copolymers are blended with other resinouspolymers such as polystyrene or polymethylmethacrylate greatimprovements in the impact strength are not realized.

According to our invention, conjugated diene block copolymers,containing from about to 80, preferably 10 to 50, weight percentlactone, based on the total monomeric composition of said conjugateddiene block copolymer, are employed to impart great improvements in theimpact strength of styrene/acrylonitrile copolymers by admixing3,649,716 Patented Mar. 14, 1972 said conjugated diene/lactone blockcopolymer and said styrene/acrylonitrile copolymer to form a blendcomposite.

Further, rubbery polymers such as polybutadiene, butadiene/styrenecopolymers, ethylene/propylene/diene copolymers, sulfur vulcanizablealkene oxide polymers, and the like, as well as resinous polymers, suchas polycarbonates, can also be employed in admixture with thestyrene/acrylonitrile copolymers and conjugated diene/lac tone blockcopolymer in preparing the blends of this invention and yet essentiallymaintain the imparted impact strength to the styrene/acrylonitrilecopolymer provided by the conjugated diene/lactone block copolymer.

The lactone containing block copolymers of this invention are employedin an amount suflicient to provide from about 5 to 60, preferably 10 to50, weight percent of said lactone containing block copolymer based onthe total weight of the blend composition.

When the remaining blend component is essentially thestyrene/acrylonitrile copolymer, it is thus employed in an amountsufiicient to provide from about 95 to 40, preferably to 50, weightpercent of said styrene/acrylonitrile copolymer based on the totalweight of blend. When other rubbery or resinous polymers are employed inadmixture with the styrene/acrylonitrile copolymer and the lactonecontaining block copolymer, the styrene/acrylonitrile copolymer willrepresent from about 40 to weight percent of the total weight of theblend composition and the lactone containing block polymer at least 5weight percent of the total weight of the blend composi tion and saidother rubbery or resinous polymer will represent not more than 50 weightpercent of the total weight of the blend composite.

The blending of the various components of this invention can beaccomplished by any convenient method known to the art with a preferredmethod employing a Brabender Plastograph. A primary desired result beingan intimate mixture of the components. The blends of this invention canbe formed with or without the use of peroxy compounds as curing agents.The polymers employed according to this invention are thus formed into ablend together with a peroxy compound, if employed, and the blendsubjected to heating either during or after blending, or both, at atemperature at or above that which causes decomposition of the peroxycompound if one is employed. Thus, the temperature and time employed inthe blending step will, in general, depend upon the choice of blendcomponents and, the presence or absence of a peroxy compound, but theseconditions will at least be sufiicient to provide said intimate mixtureof all of the blend components and to decompose the peroxy compound ifone is employed.

The peroxy compounds which can be employed in this invention includeorganic and inorganic peroxides. The term organic peroxides is meant toinclude the hydroperoxides, unless otherwise stated, and to encompasscompounds containing from 4 to 40 carbon atoms per molecule, inclusive.The organic peroxides can also be substituted with non-peroxy memberssuch as halogen, hydroxy radicals, ether and/or ester linkages, and thelike. The inorganic peroxides include calcium peroxide, barium peroxide,zinc peroxide, lead peroxide, and mixtures thereof.

Examples of suitable peroxides include: methyl npropyl peroxide, diethylperoxide, ethyl isopropyl peroxide, di-tert-butyl peroxide, di-n-hexylperoxide, n-hexyl n-decyl peroxide, dieicosyl peroxide, dicyclohexylperoxide, dicyclopentyl peroxide, bis(2,4,6-trimethylcyclohexyl)peroxide, bis(3,5-dichlorocyclohexyl) peroxide, bis(4-phenylcyclohexyl)peroxide, bis(2-cyclohexyl) peroxide, bis(4-methyl-2-hexenyl) peroxide,bis(4-octenyl) peroxide, dipropionyl peroxide, dilauroyl peroxide,dibenzoyl peroxide, dicrotonyl peroxide, dibenzyl peroxide,bis(alpha,alpha-dimethylbenzyl) peroxide, methyl 2-npropyl-3-butenylperoxide, bis(alpha-ethylbenzyl) peroxide, bis[diisopropyl (4isopropylphenyl)methyl]peroxide, bis[dimethyl(4tert-butylphenyl)methyl]peroxide, benzyl alpha-methylbenzyl peroxide,bis[4 chlorobenzoyl)]peroxide, bis(2,4-dichlorobenzoyl) peroxide, bis(2-propoxy-n-hexyl)peroxide, n-pentyl 5,8-diphenyldodecyl peroxide,bis(9,IO-dihydroxydecyl)peroxide, 2,5-di (tert-butylperoxy) 2,5dimethylhexane, bis(2-hydroxyheptyl)peroxide, tert-butyl hydroperoxide,dodecyl hydroperoxide, eicosyl hydroperoxide, triacontanylhydroperoxide, 4-methylcyclohexyl hydroperoxide, phenylcyclohexanehydroperoxide, 3-cyclohexenyl hydroperoxide, 3- phenyl 2 cyclohexenylhydroperoxide, 4-cyclophenyl-nbutyl hydroperoxide, cumene hydroperoxide(dimethylphenylhydroperoxymethane), diisopropylbenzenehydroperoxide[dimethyl (4 isopropylphenyl)hydroperoxymethane],(4-ethoxyphenyl)methyl hydroperoxide,di-nhexyl-4-hydroxyphenylhydroperoxymethane, dimethyl-(3-methoxyphenyl)hydroperoxymethane, peroxybenzoic acid, peroxybutyricacid, peroxydodecanoic acid, tert-butyl peroxybenzoate, di-tert-amyldiperoxyphthalate, and tertdodecyl peroxyacetate.

Peroxides formed by the oxidation of terpene hydrocarbons such aspinane, alpha-pinene, p-menthane, and turpentine can also be used.

The peroxides which are preferred in this invention are those whichdecompose at a temperature of at least 250 F.

The amount of peroxy compound, or compounds, employed according to thisinvention is that which will provide from about 0.25 to about 6,preferably from about 0.35 to about 4.5 gram millimoles of peroxy oxygenO-O) per 100 grams of polymers in the composition.

Styrene/acrylonitrile copolymers that can be employed according to thisinvention contain from about 5 to 50, preferably 15 to 40, Weightpercent acrylonitrile, with the remaining weight percent being styrene,based on the total weight of the monomers employed in preparing theresinous styrene/acrylonitrile copolymer. The styrene/ acrylonitrilecopolymer can be prepared by any convenient method known to the art suchas disclosed in US. Patent 2,739,142.

The conjugated diene block copolymers containing the lactone, which areemployed to impart great improvements in the impact strength ofstyrene/acrylonitrile copolymers, can be broadly represented by theformula AB, wherein A represents a block or polymer segment comprisingpolymerized conjugated diene and B represents a block or polymer segmentcomprising polymerized lactones. The B block comprises homopolymers oflactones or copolymers of two or more lactones and said lactone block orsegment comprises from about 5 to 80, preferably to 50, weight percentof the total weight of said conjugated diene block copolymer. The Ablock thus comprises the remaining 95 to 20 weight percent of saidconjugated diene block copolymer, and said A segment compriseshomopolymer prepared from conjugated dienes, copolymers prepared fromtwo or more conjugated dienes, or copolymers prepared from conjugateddiene and monovinyl-substituted aromatic hydrocarbons. When the Asegment comprises'a copolymer of conjugated dienes andmonovinyl-substituted aromatic hydrocarbons it is preferred thatsufiicient conjugated diene monomer be employed to provide a minimum oflOweight percent of polymerized conjugated diene based on the totalweight of said conjugated diene block copolymer. When the A block is acopolymer of conjugated diene and monovinylsubstituted aromatichydrocarbons these monomers can be combined in a random or block manner.Thus, for example, the lactone polymer segment B can be attached to theblock A at a polymerized diene segment or a polymerizedmonovinyl-substituted aromatic hydrocarbon segment.

Conjugated dienes containing from about 4 to 12 carbon atoms permolecule and monovinyl-substituted aromatic hydrocarbons containing fromabout 8 to 12 carbon atoms per molecule can be employed for preparingthe lactone-containing block copolymers employed according to thisinvention. v

Suitable conjugated dienes include 1,3-butadiene, isoprene, piperylene,6-phenyl-1,3-hexadiene, and the like. Suitable monovinyl-substitutedaromatic hydrocarbon compounds include styrene, alpha-methyl styrene, 4-methyl styrene, 4-isopropyl styrene, 2,4-dimethyl styrene,l-vinylnaphthalene, 2-vinylnaphthalene, alkyl derivatives thereof, andthe like.

Lactone monomers that can be employed according to this invention inpreparing said conjugated diene block copolymer containing said lactonecan be represented by the following formula:

wherein R" is one of hydrogen and a radical of the formula and when R"is a radical as specified no R is attached to the carbon atom to whichthe radical is attached, wherein R' is one of hydrogen, alkyl,cycloalkyl, alkenyl, cycloalkenyl and aryl and combinations thereof suchas alkylaryl, wherein the total carbon atoms in the R and R"substituents being in the range of 1 to 12, and wherein n being aninteger which can be 1, 3, or 4.

Suitable lactones include beta-propiolactone, delta-'vah erolactone,epsilon-caprolactone, and lactones corresponding to the following acids:

2-methyl-3 -hydroxypropionic acid, 3-hydroxynonanoic or3-hydroxypelargonic acid, Z-dodecyl-3hydroxypropionic acid,2-cyclopentyl-3-hydroxypropionic acid, 3-phenyl-3-hydroxypropionic acid,

2-( 1-naphthy1)-3-hydroxypropionic acid,2-n-butyl-3-cyclohexyl-3-hydroxypropionic acid,2-phenyl-B-hydroxytridecanoic acid,

2- Z-methylcyclopentyl -3-hydroxypropionic acid,Z-(Z-methylphenyl)-3-hydroxypropionic acid, 3-benzyl-3 -hydroxypropionicacid,

2,2-dimethyl-3-hydroxypropionic acid,

2-methyl-ihydroxyvaleric acid, 3-cyclohexyl-5-hydroxyvaleric acid,4-phenyl-5-hydroxyvaleric acid, 2-heptyl-4-cyclopentyl-S-hydroxyvalericacid, 2-methyl-3-phenyl-'5-hydroxyvaleric acid,

3 2-cyclohexylethyl) --hydroxyvaleric acid,

2- (2-phenylethyl) -4- (4-cyclohexylbenzyl) -5-hydroxyvaleric acid,

4-benzyl-5-hydroxyvaleric acid,

3-ethyl-5-isopropyl-6-hydroxycaproic acid,

2-cyclopentyl-4-hexyl-6-hydroxy-caproic acid,

3-phenyl-6-hydroxycaproic acid,

3-( 3,S-diethylcyclohexyl)-5-ethyl-6-hydroxycaproic acid,

4- 3-phenylpropyl -6-hydroxycaproic acid,

2-benzyl-5-isobutyl-6-hydroxycaproic acid,

7-phcnyl-6-hydroxy-6-octenoic acid,

2,2-di( l-cyclohexenyl)-5-hydroxy-5-heptenoic acid,

2,2-di-l-propenyl-5-hydroxy-5-heptenoic acid,

2,2-dimethyl-4-( l-propenyl -3-hydroxy-3,S-heptadienoic acid, and thelike.

The conjugated diene-lactone block copolymer as herein described can beprepared by any convenient method known to the art. Preferred processesare fully detailed in U.S. patent application, Ser. No. 883,986 by FloydE. Naylor entitled Lactone Copolymers, filed Dec. 10, 1969, now US.3,598,799). Said patent application is herein incorporated by referencethereto. Any of the methods disclosed in said patent application forpreparing the lactone containing block copolymers can be employedaccording to this invention, subject of course to any limitations hereinset forth.

As disclosed in said patent application by Floyd E. Naylor, thepreferred polymerization initiators for the foregoing monomericmaterials in preparing the conjugated diene block copolymer containingthe lactone are the organoalkyli metal polymerization initiators, andmore preferably organolithium initators. Representative of preferredpolymerization initiators are, of course, methyllithium,isopropyllithium,-n-butyllithium, sec-butyllithium, phenyllithium,dilithiomethane, and the like. Polymerization procedures employing theabove monomers and initiators are fully disclosed in said patentapplication and therefore, are not in detail described here.

The blend composites provided by this invention display high impactstrengths with a good balance of other properties including resistanceto cooking oils. The blends of this invention can also contain otheringredients normally included with such polymers such as antioxidants,pigments, dyes, fillers, stabilizers, plasticizers, and the like.

Polymeric composites produced according to this invention are useful forlining refrigerators, making molded and extruded containers, cartons,bowls, and the like. Blends of this invention have properties comparableto commercially available ABS polymers but have a lower ash content andare lighter in color than many of the ABS materials.

In addition to the above-described features of the blend composites ofthis invention, certain of the blend composites provided by thisinvention display transparency along with high impact strength. Such acombination of properties is of course highly desirable such as inpackaging applications where thermoplastic materials are desired.

It is well recognized that the opacity of commercial ABS polymers is dueto light scattering from the interfaces of the multi-phase systempresent in such materials. It is also known that a reduction in particlesize of the dispersed phase(s) below that of the wavelengths of visiblelight reduces the opacity of such blends but produces no improvement inthe physical properties of the brittle component of said blends, i.e.,no reinforcement effects are obtained. However, essentially transparentimpact plastic compositions of this invention can be obtained by closelymatching the refractive indices of the phases in said blends, i.e., thetwo phases are believed to be the (a) lactone block with saidstyrene/acrylonitrile copolymer, and (b) the remainder of the lactoneblock polymer. That this technique can be employed with blends of thisinvention to produce essentially transparent compositions isparticularly surprising in that it was found that a number of lactoneblock polymers all had refractive indices lower than thestyrene/acrylonitrile copolymer employed in preparing the blends. Sinceit is believed that the lactone block of the conjugated diene blockcopolymer containing said lactone block formed a solution with thestyrene/ acrylonitrile copolymer then the refractive index of this solidsolution and that of the remainder of the lactonecontaining blockpolymer could be calculated and shown to be closely matched for thoseblends of this invention which are essentially transparent. The abovecalculations were made by assuming that a linear relationship betweenthe composition of the copolymers and their refractive indices based onthe refractive indices of the respective homopolymers existed. Thesuccess of these assertions provides additional strong evidenceregarding the true compatibility of the lactone block in thelactone-containing block polymers with the styrene/acrylonitrilecopolymer.

Illustrative of the foregoing discussion and not to be interpreted as alimitation on the scope thereof, or on the materials herein employed,the following examples are presented.

EXAMPLE I Various polymer blends are prepared to demonstrate the abilityof the lactone containing block copolymers of this invention to greatlyimprove the impact strength of styrene/acrylonitrile copolymers and tofurther demonstrate the comparative ineffectuality of various otherrubbers to achieve the same result.

Thus, blends were prepared from various rubbery polymers and/orstyrene/butadiene/epsilon-caprolactone block polymers withstyrene-acrylonitrile resin. The procedure employed in these runs was tomeasure the properties of the blends in which the rubbery polymer wasused to replace various proportions, or all of the lactone-containingblock polymer, in the blends while maintaining the sum of the butadieneplus lactone content in the blends at a constant level in an attempt tomaintain the flexural modulus at an essentially constant value in orderto more clearly see the effect of the lactone block segment on theimpact strength of the blends.

The blends were prepared by the use of a Brabender Plastograph internalmixer in which the mixing chamber was first heated to 145 C. by means ofan oil bath. The mixing chamber was then purged with nitrogen. Thepolymers added to the chamber were then fluxed together in a nitrogenatmosphere while the rotors of the mixing head were rotated at about 10revolutions per minute (r.p.m.). The tiuxed mass was then mixed atr.p.m. for 3 minutes m a nitrogen atmosphere. 0.1 part by weight of bis-(alpha,alpha-dimethylbenzyl) peroxide, i.e. Dicup, was added to eachblend after the mixer was slowed to about 10 r.p.m.s and a vacuumapplied to the mixing chamber. When the vacuum was equivalent to 30inches of mercury the mass was mixed for 7 minutes at 100 r.p.m.

Test specimens were then prepared by compression molding the blends at350 F. under about 1,100 pounds/ square inch pressure. The procedureused was to preheat the sampel under slight mold pressure for about 4minutes then at about 1,100 lbs/sq. in. for about 4 minutes longer.

The blend composition and properties of the blends are reported in TableI.

The results reported in Table I clearly demonstrate the impact strengthof the styrene/acrylonitrile copolymer is greatly improved by theadmixture of the lactone containing block copolymer. Thestyrene/acrylonitrile copolymer is very sensitive to the presence ofsaid lactone containing block copolymer and the impact strength thereoffalls off to a very low value when no lactone-containing block c0-polymer is present. It should be noted that only comparative slightincreases in impact strength of the styrene/ acrylonitrile copolymersare obtained by admixture of rubbery polymers not containing saidlactone. It should also be noted that the impact strengths demonstratedby the blends of this invention are among the highest known for impactplastics of any type.

8 EXAMPLE III Blends of styrenelbutadiene/e-caprolactone (25/50/25)block copolymer with a styrene/acrylonitrile (77/23) co- TABLE I PartsIzod Replaoe- Flexnral Elongaimpact Lactone ment, d Molt flow! modulus,Tensile) tion, lb. lineh Run No SAN, polymer, Rubber percent g./l0 min.p.s. p.s 1 percent notch 77. 0 0. 21 297, 000 5, 250 54 11. 62 78. 1 1.7 0. 19 300, 000 5, 040 59 11. 93 78, 9 1. 2 25 0. 19 289, 000 5, 160 9212. 25 B0, 3 8. 4 5O 0. 24 311, 000 5, 100 65 7. 67 81, 7 12. 7 75 0. 44320, 000 4, 640 1. 39 83, 1 1e. o 100 0.76 322, 000 4, 700 3 n. 37 77, 52. 3 10 0. 20 283, 000 5, 050 27 10. 77 5 5. 6 25 9. 20 292, 000 5, 12045 12. 18 77 5 11. 2 50 0. 33 289, 900 4, 810 89 8. 20 77 5 16.9 75 0.37 287, 000 4, 160 l. 66 77, 5 22. 5 100 0. 91 286, 000 4, 380 10 0. 3374, g 5. 0 10 0. 17 274, 000 4, 890 33 11. 90 71 1 l2. 0 25 0. 16 260,000 4, 710 66 12. 32 64, 7 24. 0 50 0. 19 240, 900 4, 100 63 2. 60 58. 136. 3 75 0. 32 241, 000 3, 860 24 1. 37 51 6 48. 4 100 0. 58 222, 000 3,350 10 0. 60

*Trademark. Tyril 767, a styrenelaerylonitrile (77/23) copolymer made byDow Chemical Co. Izod impact 1b.]in. notch, 0 26 (25/50/25) blockoopolymer, having 01 82.

EXAMPLE II Blends were made according to the process of Example I todemonstrate the ability of a lactone polymer to greatly improve theimpact strength of a styrene/acrylonitrile copolymer if said lactone isemployed as a block copolymer containing said lactone in contrast to alactone homopolynitrile copolymer was blended with a lactone containingblock copolymer according to this invention. In the remer. Accordingly,in Runs 1, 4, and 6, the styrene/acrylomaining runs thestyrene/acrylonitrile copolymer was blended with polycaprolactonehomopolymer and butadiene/styrene block copolymers to provide anequivalent percentage or greater of lactone to the styrene/acrylonitrilecopolymer. The blend composition and properties of the blends arereported in Table II.

f A butadiene/styrene (75/25) block copolymer having a block polystyrenecontent of about 18% and a M oney viscosity (ML4 at 212 F.) of 42-52made by Phillips 8 A butadiene/styrene content of about h ASTMD-1238-62T (200 (3., 5,000-gram load).

fASTM D-790-63.

I ASTM D638-61T at 0.2 inches/minute drawing rate.

ASTM D-256-56 (73 F., y -inch sample thickness).

(35/65) oopolymer having a block polystyrene EXAMPLE IV Blends were madeaccording to the process employed in Example I by blending the lactonecontaining block copolymer of this invention with various resinouspolymers to demonstrate that the high impact strengths imparted tostyrene/acrylonitrile copolymers according to this invention are notrealized with other resinous poly- TABLE II Parts e Melt Izod Polyflow,Elongaimpact Block capro g. /10 Flexural Tensile, tlon, lb. /in. Run NoSAN polymer lactone, min mod., p.s.i. p.s. percent notch i 77. 5 b 22. 50 21 297, 000 5, 250 54 11. 62 77. 5 16. 9 5. 6 2. 344, 000 5, 050 21 0.64 77. 5 d 16. 9 5. 6 1. 87 307, 000 4, 570 21 0. 69 67. 3 e 32. 7 0. 15296, 000 4, 880 45 7. 54 67. 3 1 24. 6 2 1. 95 302, 000 4, 090 39 0. 8485 B 15 0. 31 314, 000 5, S40 17 8. 58 85 h 11. 3 3. 7 1. 40 363, 000 5,490 8 0 42 Trademark. I Parts by weight. b Astyrenelbutadiene/caprolaetone (25/50/25) block polymer.

Solpreno 406, a butadiene/styrene (60/40) block polymer having about 35%block styrene content.

5 Solprene 408, a butacllene/styrene (70/30) block copolymer.

6 A styrene/butadiene/caprolactone (47.5/21525) block polymer. 1Solprene 407, a butadienestyrene (35/65) block polymer.

I A butadiene/caprolactone (/25) block polymer.

5 Solprene 200, a polybutadiene.

1 Prepared by polymerization oi-S-eaprolactone in cyelohexane withn-butyllithium, MW., about 50,000.

1 See footnote Table I. Norm-0.1 parts by weightol Dlcup employed in allblends.

The above example clearly demonstrates the tremendous improvements inimpact strength imparted to the styrene/ acrylonitrile copolym'er whenblended with a block copolymer containing the lactone according to thisinvention.

mers such as polystyrene and polymethylmethacrylate. The mutualsolubility between styrene/acrylonitrile copolymers and the lactonecontaining block'copolymers is believed to be a principal factor inachieving this realiza- 75 tion.

The blend compositions and properties of the blends are reported inTable IV. All of the blends contained 0.1 weight percent by weight ofbis(a,a-dimethylbenzyl)peroxide. The polymer components are reported asparts by weight of the total blend in Table IV.

TABLE III no sign of the polycaprolactone (A) transitions were seen inthese blends.

The above results demonstrate that the polycaprolactone (A) andstyrene/acrylonitrile (B) form a homogeneous solid solution. It isfurther demonstrated that blends of Parts by weight Blend Recipe:

BSC=Butadiene/styrene/epsilon caprolactone (50/25/25) polymer Variable.SBC=Styrene/butadiene/epsilon caprolactone (/50/25 polymer 1 Do.SAN=Styrene/acrylonitrile (77/23) polymer Do. Ci0L1D=blS(cz,a-dimetbylbenzyl)peroxide. Do.

Results Parts by weight Izod Elonga- Fluxural Melt impact, $130 orTensile, tion. modulus, flow, ft. lb./in. Run No BSO SAN, b Dicut p.s 1percent p.s.i g./10 min. notch 1 100 9, 870 4 524, 000 1. 80 0. 26 e 37.5 65. 2 2, 870 189, 000 1.32 11. 79 l 37. 5 62. 5 0. 1 3, 160 42 219,000 0. 52 10. 38 H 30.0 70.0 0.1 4, 060 71 238,000 0.33 11. 73 e 22. 577. 5 0.1 5,100 41 294, 000 0. 45 10.00 B 37. 5 62. 5 0. 1 2, 570 6 195,000 0. 38 2, 31

liglgl nier gizaving an inherent viscosity of 1.34 determined inchloroform using procedure of U.S. 3,078,254, co

b ASTM D-fi3S-61T at 0.2 inch/minute drawing rate. it ASTM D-638-61T asin d ASTM D-790-63.

B ASTM D-1238-62T (200 C., 5.000 gram load).

! ASTM D-256-56 (73 F., A inch sample thickness).

K Polymer having an inherent viscosity of 0.91 in chloroform asdetermined in 11 See footnote Table I.

e Styrene/butadiene/eaprolaetone (25/50/25), see footnote Table I. bStyrene/acrylonitrile (77/23), see footnote Table I.

e As reported/in footnotes, Table I.

I! Cosden 550 made by Cosden Oi] and Chemical Co.

s Plexiglas V-lOO made by Rohm and Haas Co.

EXAMPLE V Dynamic modulus data were obtained on (A) polycaprolactone,(B) styrene/acrylonitrile (77/23) copolymer, (C) blends of (A) and (B)above and (D) blends of (B) with butadiene/caprolactone block copolymer.Dynamic storage and loss modulus vs. temperature curves were obtained onthe above materials using a Vibron Dynamic Viscoelastometer.

The results of these determinations were as follows: Material (A)polycaprolactoneshowed two transition regions, glass transition at 40 C.and a crystalline melting region; Material (B)styrene/acrylonitrilecopolymershowed only a glassy transition at 104 C.; Material (C)--blendsof (A) and (B)showed only glassy transition with the position(temperature) of the loss modulus maximum varying with blendcomposition. It was noted that a plot of l/T max vs. blend compositionwas linear for these blends which is a characteristic of randomcopolymer Tg values in terms of Tg of the homopolyrners; Material(D)-blends of (B) with butadiene/caprolactone block copolymershowed apolybutadiene transition at 70 to 80 C. and a double peak in the storagemodulus for caprolactonestyrene/ acrylonitrile phase. One of the peaksis the glassy transition peak seen in Material (C) while the second isbelieved to be due to chain entanglements. Again, as in (C),

the butadiene/caprolactone block copolymer with styrene/ acrylonitrilecopolymer then are represented as particles of polybutadiene dispersedin the polycaprolactone blockstyrene/acrylonitrile solid solution.

EXAMPLE VI Blends were prepared according to the blending. proceduresemployed in Example I. The blend compositions are reported in Table V.The properties of the various blends employed in Table V are reported inTable VI.

TABLE V.RECIPE Styrene/aorylonitrile Polycarbonate bStyrene/butadiene/caprolactone Butadiene/oaprolactone d SolpreneZOO 10Solprene1205 Polycaprolactone K 21a Polystyrene 40 TABLE VI Izod ElongrvFlexural impact, I Run No Tensile, tion, modulus, lb./inch p.s.i.percent p.s. notch Determined as reported in Table I.

The data reported in Table VI demonstrate that blends ofstyrene/acrylonitrile copolymers and the lactone containing blockcopolymer can be admixed with other resins such as polycarbonates andstill maintain high impact strength that are imparted to thestyrene/acrylonitrile copolymers according to this invention, asdemonstrated in Runs 1 and 2. Substitution of a polybutadiene rubber, ora butadiene/ styrene block copolymer and a homopolymer of a lactone, forthe lactone containing block copolymer of this invention, represented byRuns 3 and 4 were contrarily ineifective for imparting the high impactstrengths to the styrene/acrylonitrile copolymer. Substitution ofpolystyrene for the styrene/acrylonitrile copolymer employed accordingto this invention is likewise ineffective as demonstrated by Run 5. Run6 clearly demonstrates that a rubber can also be blended with the blendcomposite of this invention.

EXAMPLE VII Blends were prepared according to the blending proceduresemployed in Example I for the purpose of pro ducing an essentiallytransparent composition. In these runs styrenelbutadiene/caprolactone(S/B/C) block copolymers of vraying composition were blended with astyrene/acrylonitrile (77/23) copolymer (SAN) in varying ratios.Refractive indices (R.I.) were calculated for the lactone block polymer,for the continuous phase assuming the caprolactone block formed asolution with the SAN in this phase, and for the dispersed phase,styrene! butadiene portion of the lactone-containing block copolymer,assuming in each case a linear relation between composition andrefractive index based on the refractive indices of the respectivehomopolymers. The blend compositions are shown below in Table VII andthe properties of the blends shown in Table VIII.

TABLE VII Calculations based on the following values for the respectivehomopolymers or copolymer:

Polystyrene. 1.600. Polybutadiene, 1.518. Polyacrylonitrile, 1.519.Polycaprolactone, 1.480 Poly(styrenelaerylonitrile) 1.580 b All blendscontained 9 weight percent polybutadiene.

TABLE VIII Izod im- Melt flow Modulus Elongapa b Run Haze, I gJlO p.s.i.X Tensile, b tion, b it. lb./in. No. percent min. 10- p.s. percent notcha ASIM D 1003-52. 5 Determined as reported in Table I.

The results in Tables VII and VIII demonstrate that by proper selectionof the blend components and blend ratios, compositions possessing verygood physical properties such as impact strength as well as hightransparency can be prepared according to this invention. Run No. 5above is an outstanding example of a composition of this type.

As will be evident to those skilled in the art, various modifications ofthis invention can be made or followed in light of the discussion anddisclosure herein set forth without departing from the scope or thespirit thereof.

We claim:

1. A composition comprising from about 5 to 60 weight percent of aconjugated diene/lactone block copolymer containing from about 5 toweight percent lactone and from about 95 to 40 weight percent of astyrene/acrylonitrile copolymer containing from about 5 to 50 weightpercent acrylonitrile.

2. A composition according to claim 1 wherein said composition comprisesfrom about 10 to 50 Weight percent of said conjugated diene/lactoneblock copolymer and from about to 50 weight percent of said styrene/acrylonitrile copolymer.

3. A composition according to claim 1 wherein and said conjugateddiene/lactone block copolymer can be represented by the formula AB,wherein A represents a block segment comprising polymerized conjugateddienes, and B represents a block comprising polymerized lactones,wherein said A block represents from about to 20 weight percent of thetotal weight of said block copolymer and comprises homopolymer preparedfrom conjugated dienes, copolymers prepared from 2 or more conjugateddienes, or copolymers prepared from conjugated dienes andmonovinyl-substituted aromatic hydrocarbons, and when the A blockcomprises a copolymer of conjugated dienes and monovinyl-substitutedaromatic hydrocarbons sufiicient conjugated diene monomer is employed toprovide a minimum of 10 weight percent of polymerized conjugated dienebased on the total weight of said block copolymer; wherein said B blockcomprises homopolymers of lactones, or copolymers of 2 or more lactones.

4. A composition according to claim 3 wherein said styrene/acrylonitrilecopolymer comprises from about 15 to 40 weight percent acrylonitrile andwherein said conjugated diene/lactone block copolymer comprises fromabout 10 to 50 weight percent polymerized lactone based on the totalweight of said conjugated diene block copolymer.

5. A composition according to claim 4 wherein said conjugated diene isbutadiene, wherein said monovinylsubstituted aromatic hydrocarbon isstyrene and said lactone is e-caprolactone.

6. A composition according to claim 1 comprising in addition a peroxycompound curing agent containing from about 4 to 40 carbon atoms permolecule.

7. A composition according to claim 1 wherein said composition istransparent.

References Cited UNITED STATES PATENTS MELVIN GOLDSTEIN, PrimaryExaminer U.S. Cl. X.R. 260873

